Japanese maple

Sun

Partial shade, ideally morning sun and afternoon shade. Full sun is suitable in cooler climates where soil stays moist; protect from hot afternoon sun and drying winds.

Water

Keep the root zone evenly moist but never waterlogged. Water deeply during dry spells, especially during the first two growing seasons; container plants need more frequent checks.

Soil

Moist, well-drained soil rich in organic matter, preferably slightly acidic to neutral. Avoid waterlogged ground, compacted soil and very alkaline conditions.

Height

15-25 ft (4.6-7.6 m); many garden cultivars remain much smaller

Spread

10-25 ft (3-7.6 m), depending on cultivar

Flowers

Small reddish-purple flowers in spring, often partly hidden by the emerging leaves.

Foliage

Opposite, hand-shaped leaves, usually with five to seven pointed, toothed lobes. Green, red, purple or variegated foliage depends on cultivar; autumn colour can be yellow, orange or scarlet.

Growth

Slow to moderate, depending on cultivar and growing conditions.

Care needed

Medium

• Plant with the root flare at soil level, in a position sheltered from strong wind and late-frost pockets.
• Water deeply when the upper soil begins to dry; do not leave pots standing in water.
• Apply 2-3 in (5-8 cm) of organic mulch over the root zone, keeping it clear of the trunk.
• Feed lightly in spring only if growth is weak or soil is poor; avoid high-nitrogen feeds.
• Stake only if the root ball moves in wind, using a low, flexible tie; remove the support once roots are secure.
• For containers, choose a compact cultivar and a pot with generous drainage holes; protect the root ball from severe winter freezing.

Pruning. Prune lightly in late summer or midwinter, avoiding the spring sap-flow period. Remove dead, damaged or crossing branches and any shoots below a graft; retain the natural framework rather than shearing or topping.

Late winter

Check stakes and ties, and inspect the branch structure before leaves emerge.

Spring

Refresh mulch and give a light feed only if needed; protect newly opening leaves when a late frost is forecast.

Early summer

Check soil moisture regularly, especially around newly planted trees and in containers.

Summer

Water deeply during dry weather and watch for leaf scorch on exposed plants.

Late summer

Carry out any light shaping and remove unwanted shoots below the graft.

Autumn

Plant while soil is workable and moist, allowing time for roots to establish before severe cold.

Winter

Insulate exposed containers in cold regions and keep their drainage holes clear.

• Use an upright tree as a focal point beside a lawn or terrace, leaving room for its mature canopy.
• Place a weeping cultivar beside a path or pond where its branching outline can be seen clearly.
• Underplant with ferns, hostas and hellebores for a layered woodland planting.
• Grow a compact cultivar in a large container in a sheltered courtyard.
• Set autumn-colouring forms against dark evergreens to make the seasonal colour stand out.

Garden styles it suits: Japanese, Zen dry garden, Woodland, Japandi, Modern courtyard and Autumn colour.

Plant it with: Hostas, Epimediums, Hellebores, Japanese painted ferns, Azaleas and Japanese forest grass.

Wildlife: Flowers provide some food for visiting insects, seeds are eaten by some birds and small mammals, and branches offer shelter. Outside its native range, it generally supports fewer specialist insects than locally native trees.

• Leaf scorch: brown edges usually follow drought, hot sun or drying wind. Check root-zone moisture, mulch and provide afternoon shade; damaged leaves will not recover.
• Late-frost damage: young leaves may blacken or collapse. Protect small trees with horticultural fleece when frost is forecast, and wait for replacement growth before pruning.
• Verticillium wilt: sudden branch wilt or dieback can indicate this soil-borne disease. Seek a diagnosis, remove dead wood and replace a severely affected tree with a less susceptible plant.
• Root rot: persistent wet soil can cause poor growth, wilting and root decay. Correct drainage and avoid overwatering; badly affected trees may need replacement.

Japanese maple is not known to be toxic to cats, dogs, horses or people, and no part is established as poisonous in normal garden exposure. Do not confuse it with red maple (Acer rubrum), whose wilted or dried leaves can cause fatal poisoning in horses; keep unidentified maple leaves out of paddocks and hay.

Where it spreads. Can self-seed into nearby woodland and is considered locally invasive in parts of the eastern United States, particularly the Mid-Atlantic. Check local guidance before planting near natural woodland and remove unwanted seedlings.

• Full-moon maple (Acer japonicum)

  Typically has larger, rounder leaves with seven to eleven broad lobes and more conspicuous hairs, especially when young.

• Golden full-moon maple (Acer shirasawanum)

  Usually has rounded leaves with nine to thirteen relatively shallow lobes; its winged fruit is often held upright above the foliage.

• Korean maple (Acer pseudosieboldianum)

  Usually has nine to eleven lobes and noticeably hairy young leaves and leaf stalks; Japanese maple leaves are generally less hairy.

The epithet palmatum refers to the hand-like shape of the leaves, while Japanese maple reflects its association with Japan.

Propagation. Grow the species from fresh seed given a suitable cold, moist period; germination can be slow and uneven. Seedlings do not reliably match named cultivars, which are usually propagated by grafting.

Accepted botanical name

Acer palmatum

In the US and Canada

Introduced in Canada and the lower 48 states.

Native range

Japan and Korea.

Measured

Soil pH 6.5 to 7. Average height 700 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.